In general, LPG fuel stored in a vehicle engine LPG tank (which is also called a bombe) is vaporized in the vaporizer and then blended with exterior air in the mixer for supply into the engine cylinder. However, in the case of an LPI engine using LPG as fuel, the fuel is directly injected into the cylinder via an injector for combustion. LPI engines have gradually increased in usage due to the potential for more accurate fuel injection control.
Propane and butane are employed as main ingredients of LPG. A typical LPG fuel contains 10–30% of propane in consideration of the harsh seasonal conditions. The fuel injection control is performed by a fuel injection control map rendered on the basis of typical LPG fuel.
The Engine Control Unit (ECU) pre-saved with such a fuel injection control map receives fuel injection control conditions, e.g., fuel pressure and fuel temperature, via a separate fuel pressure sensor and fuel temperature sensor.
However, conventional LPI engines can exhibit notable drawbacks, specifically improper performance of the fuel injection control when LPG with differing contents of propane is employed, causing a deterioration of the vehicle start, increase in fuel consumption, reduction in engine output, increase in toxic exhaust gas, and the like.
Another drawback that conventional LPI engines can exhibit is that separate sensors for measuring fuel pressure and fuel temperature can be required to control the fuel injection via the ECU.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art that is already known to a person skilled in the art.